首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
The study was conducted to investigate fasting effect on flesh composition and antioxidant defenses of market-size large yellow croaker (Pseudosciaena crocea). Two hundred fish (main initial weight 380 g) were divided into two groups (control and fasted) and reared in 6 cages. After two weeks of adaptation, group I fasted for 28 days; group II was fed normally as a control. In 3, 7, 14, 21 and 28 days, 6 fish per group were processed for proximate flesh composition, liver antioxidant enzyme activities and malondialdehyden flesh content analyses. In fasted fish, the reduction of lipid content in muscle occurred after day 3, and, compared to controls, the content of protein decreased from day 21, the activities of liver antioxidative enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) increased from day 3, and flesh malondialdehyde (MDA) levels increased from day 21. Muscle lipid reduction shows that the fasting technique is effective in end product improvement of large yellow croaker. However, considering flesh protein loss and the subsequent oxidative stress, the fasting technique should be used with precautions.  相似文献   

2.
The effect of trawling on fish size and on different quality parameters of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) was evaluated after conducting 16 valid hauls using two trawls in a double rig fitted with a traditional and a novel ‘T90’ codend, respectively. The total catch volume during the fishing period was 47.6 metric tons, with an average catch per codend of 1.5 (range 0.5–2.9) tons. The mean haul duration was 5 h. The catch was assessed according to fish size, mortality, external damage, initial white muscle pH and development of rigor mortis. Fillet quality (colour, blood spots, gaping) was assessed after 1 week of freeze-storage. Our results showed there was no difference between the two types of nets in terms of catch volume, but significantly slightly bigger fish were caught with T90 than with the traditional trawl net (p < 0.05). Haddock caught with the traditional trawl net had more external injuries related to the trawl gear than haddock caught with the T90 gear (p < 0.05). The gaping frequency for cod caught with the traditional trawl net tended to be higher than cod caught with the T90 gear, but the difference was not significant (p = 0.07). No other differences in fish quality between fish caught in the trawl nets were observed.  相似文献   

3.
Supplementing fish feed with Arthrospira platensis has several beneficial effects, such as improved growth, survival and feed conversion, but little is known about how it affects gut microbiota or flesh quality. In this trial, feed with 3% A. platensis was given to Oreochromis niloticus (SPR, spirulina supplemented) over a period of 50 days and their gut microbiota and flesh quality were compared with controls (CTRs, no supplementation). Average daily growth was higher in SPR fish (p < 0.05). Regarding microbiota, a total of 5,470,272 readings (individuals) were obtained from 16 gut samples (n = 8 CTR, n = 8 SPR), with a gamma diversity of 1,563 species but no significant differences were found between treatments. Among the high inter‐individual variability found, some individual microbiota were dominated by Proteobacteria (36.6%) and Fusobacteria (32.9%) and others more by Actinobacteria (37%). Regarding flesh quality, significant differences were observed in flesh colour post‐mortem (a*, b* and chroma) (p < 0.05), with higher reflectance in the range of 470–500 and 620–670 nm in SPR tilapia, which corresponds with the reflectance range of β‐carotene and phycocyanin. However, rigor mortis was resolved earlier in SPR fish (p < 0.05), which suggests a shorter shelf life. Adding 3% of A. platensis in O. niloticus diet can improve growth and flesh colour and does not appear to modify intestinal microbiota.  相似文献   

4.
An 8‐week feeding trial was conducted to evaluate the effects of fish meal (FM) replacement by rice protein concentrate (RPC) with supplementation of microcapsule lysine (ML) or crystalline lysine (CL) on growth performance, muscle development and flesh quality of blunt snout bream. Four isonitrogenous and isoenergetic diets were formulated, including FM diet (containing 50 g/kg FM), RPC diet (FM replaced by RPC), MRPC diet (FM replaced by RPC with ML supplementation) and CRPC diet (FM replaced by RPC with CL supplementation). Fish fed FM diet had significantly higher weight gain, feed efficiency, protein efficiency ratio and nitrogen and energy utilization than that of RPC group, but showed no statistical difference with other treatments. In addition, fish fed RPC diet showed higher muscle fibre frequency in the 20‐ to 50‐μm class but lower >50‐μm class and higher cooking loss than that of the other groups. Furthermore, no significant difference was found in whole‐body proximate compositions, frequency distribution of <20‐μm‐diameter fibres, texture, muscle content, collagen, pH 24 hr post‐mortem and sensory quality. The results showed that RPC supplemented with ML or CL could replace fishmeal without any adverse effects on growth performance and flesh quality for blunt snout bream.  相似文献   

5.
Common carp were fasted for 0, 3 and 14 days prior to exposure to a 2‐hr crowding stress. Serum cortisol, glucose, lactate, T4, T3, serum alternative complement (ACH50), lysozyme, total immunoglobulin (Ig) and blood WBC were determined before and 0, 6 and 24 hr after the crowding stress. Three days of fasting led to a significant decrease in serum levels of lactate and thyroid hormones. Fourteen days of fasting led to initiation of physiological process to maintain serum glucose by increase in serum cortisol level and lactate utilization. These fish had lower levels of thyroid hormones suggesting suppression of basal metabolism. The fish also had lower WBC and serum lysozyme and total Ig levels indicating immunosuppression. After the crowding stress, the fish fasted for 3 days had significantly lower lactate, thyroid hormones and total Ig levels. The fish fasted for 14 days had higher cortisol but lower glucose and thyroid hormones levels suggesting impairment in metabolic responses to the crowding stress. Immunological and health indicators including WBC, and ACH50, lysozyme and total Ig of these fish were significantly lower than the other groups after the crowding stress. Overall, the results show that a 14‐day fasting leads to stress responses, reduction in metabolism and immunosuppression. Moreover, 14 days of fasting lead to greater cortisol response to a further crowding stress, which induces marked immunosuppression and fallen welfare.  相似文献   

6.
Salmon farms attract large amounts of wild fish, which prey on uneaten feed pellets. The modified diet of the wild fish aggregating at salmon farms may reduce the flesh quality of the fish, influencing the local fisheries. We compared the quality of saithe (Pollachius virens) captured near (farm associated—FA) or more than 5 km away (un‐associated—UA) from salmon farms in Norway. The fish were captured during summer, autumn and spring using two commercial fishing methods (jigging and bottom nets). Overall, the fillet quality of FA saithe was good, although it was clearly reduced for almost 10% of the catch. Moreover, the quality of the FA saithe was significantly reduced compared with UA saithe, but the differences were small. Our results also showed that fish caught with jigging had better quality than fish caught with nets, and that fish that died in the nets were of lower quality than fish that were alive after hauling. There was no clear variation among seasons in fillet quality. Although no major and overall differences in quality were found between FA and UA saithe, reduced quality for even a modest proportion of the fish may influence the value of the total catch.  相似文献   

7.
The study was to investigate effects of dietary chlorogenic acid (CGA) on growth performance, flesh quality and serum biochemical indices of grass carp (95.1 ± 0.3 g) (Ctenopharyngodon idella) fed seven different diets, including control diet, Eucommia ulmoides (EU)‐supplemented diet (20 g kg–1) and CGA‐supplemented diets containing 100, 200, 400, 600 and 800 mg/kg CGA. Contents of collagen and alkaline‐insoluble collagen in muscle and skin were significantly increased by dietary CGA and EU (p < .05). Total essential amino acids (TEAA) and total amino acids (TAA) in muscle of grass carp fed EU diet or 400, 600 and 800 mg/kg CGA diet were significantly higher than those of fish fed control diet and 100 and 200 mg/kg CGA diet (p < .05). Fish fed 200–800 mg/kg CGA showed significantly lower muscle crude lipid content than EU, control and 100 mg/kg CGA groups (p < .05). Fish fed CGA‐supplemented diets (100–800 mg/kg) had significantly higher muscle fibre density and lower muscle fibre diameter than control group (p < .05). In conclusion, supplementation of CGA improved flesh quality of grass carp, and supplemental level of CGA for improving flesh quality and growth was estimated to be 400 mg/kg diet.  相似文献   

8.
The present investigation has been conducted to study the effect of different sublethal concentrations of arsenic (5, 10 and 15 mg/L) on the muscle glycogen content in an Indian teleost, Clarias batrachus, during their post-spawning period (October to January).The species were exposed to various arsenic concentrations for six consecutive days i.e.,144 h. Significant differences in average muscle glycogen content were found in the treated male and female C. batrachus specimens. However, significantly higher (P < 0.01) muscle glycogen content was observed in male fish when compared to females in the untreated specimens. Arsenic caused muscle glycogenolysis in both sexes of C. batrachus. The depletions were not always dose (arsenic concentration) and time dependent, although higher concentrations were more glycogenolytic than the lower concentrations. After 96 h of treatment with arsenic, less depletion of muscle glycogen content was recorded in both sexes of fish.  相似文献   

9.
This study was carried out to determine the differences in proximate and fatty acid (FA) compositions in different flesh cuts of the most valuable cephalic portion of cultured (full-cycle), cultured fasted (full-cycle), and wild Pacific bluefin tuna (PBT; Thunnus orientalis). Cultured fasted PBTs were fasted for 6 days to ensure empty stomachs during harvesting and to determine the influence of fasting on the lipid and FA composition in different flesh cuts. Significantly higher lipid contents were observed (p < 0.05) in the dorsal akami (lean part) and the ventral o-toro (very fatty part) flesh cuts in cultured and cultured fasted PBTs than in wild ones. However, monounsaturated fatty acid (MUFA) contents in all flesh cuts were significantly higher in cultured and cultured fasted PBTs than in wild PBT. Wild PBTs contained significantly higher (p < 0.05) polyunsaturated fatty acid (PUFA) contents than other cultured PBTs in all flesh cuts except for the dorsal akami and wakaremi (fatty part near dorsal fin) flesh parts, and contained higher n-3 FA content than other PBTs—especially docosahexaenoic acid (DHA, C22:6n-3)—in the lipid fraction from the dorsal chu-toro (medium fatty part), ventral akami, ventral chu-toro, o-toro, and in dark flesh cuts. The flesh quality of cultured or cultured fasted PBTs has the advantage of having a higher total amount of essential FAs than that of wild PBT.  相似文献   

10.
Supranutritional dietary selenium (Se) has been demonstrated beneficial for fish health, however, its effects on fish flesh quality remain unclear. This study investigated the effects of supranutritional dietary Se on the flesh quality of rainbow trout (Oncorhynchus mykiss) and their potential mechanism. Fish were fed a basal diet supplemented with or without graded Se yeast for 10 weeks. Results showed that Se supplementation significantly increased fillet crude protein and enhanced fillet water‐holding capacity as well as fillet firmness. Supplementing with both 2 and 4 mg/kg Se significantly downregulated the expressions of two autophagy–lysosome‐related genes (autophagy‐related 12‐like and gamma‐aminobutyric acid type A receptor‐associated protein‐like 1) in fish muscle, while supplementing with 4 mg/kg Se also significantly downregulated the expression of two ubiquitin–proteasome‐related genes (muscle RING finger 2 and F‐box protein 25). Correlation analysis indicated that the improved fillet quality parameters were closely correlated with the expressions of these differentially expressed genes. This study revealed that dietary Se was effective for the improvement of rainbow trout flesh quality, and the improved fish flesh quality was associated with the inhibited protein degradation in fish muscle.  相似文献   

11.
  相似文献   

12.
Possible effects of short‐term starvation on flesh quality in Arctic charr were studied in spring (March) and summer (August). Groups of juvenile Arctic charr (mean weight March 536 g ± 24; August 461 g ± 15 SEM) were starved for 1, 2 and 4 weeks (March) and 1, 2 and 3 (August). After each starvation period, the fish were slaughtered, and flesh samples collected in order to investigate quality and textural properties in the different experimental groups. Starvation had a positive effect on flesh quality giving firmer texture and lower gaping scores. Starved fish had lower cathepsin activity at slaughter, and a similar difference was seen one‐week post mortem. The results showed that the effect of starvation period was seasonally dependent. Starvation had a larger effect in summer, where a three‐week starvation resulted in firmer texture, whereas this was not seen during spring.  相似文献   

13.
Possible interactive effects of temperature and photoperiod on flesh quality in Atlantic salmon post‐smolts were studied. Juvenile (initial mean weight 96.0 g ± 3.1 SEM) Atlantic salmon were reared at six different combinations of temperatures (4.3, 6.5 or 9.3°C) and photoperiods (continuous light or simulated natural photoperiod). At termination of the trial, the fish were slaughtered and flesh samples taken to investigate quality and textural properties in the different experimental groups. Final weight in the six experimental groups varied between 174 and 345 g. Softer texture was seen in the fast growing groups. Photoperiod has only minor effect on flesh quality and textural properties, whereas temperature had significant impact on most of the measured variables. Although positive for growth, higher temperatures might be less favourable in relation to softer muscle tissue.  相似文献   

14.
To investigate the effects of dietary vitamin C on growth, flesh quality and antioxidant capacity of juvenile golden pompano Trachinotus ovatus, a 56‐day feeding trial with five graded levels of dietary VC (D1: 11.69, D2: 34.89, D3: 59.10, D4: 114.26 and D5: 227.93 mg VC per kg of diet) was performed on 375 fish (triplicate groups of 25 fish per diet, initial weight 13.57 ± 0.09 g). Results showed that fish of D3 group exhibited the maximum specific growth rate (SGR) and the highest liver enzymatic activities of catalase (CAT) and glutathione peroxidase (GSH‐PX), which were consistent with the expression levels of cat and gsh‐px. Besides, the D3 group also showed higher contents of protein and lipid, and lower cooking loss, drip loss and malondialdehyde content in muscle than D1 group. The docosahexaenoic acid proportion in muscle increased with increasing dietary VC levels. Furthermore, the lowest expression levels of carnitine palmitoyltransferase1 (cpt1) and peroxisome proliferator‐activated receptor α (pparα) were detected in livers of D3 group. The optimum dietary VC level was 49.73 mg/kg from the broken‐line analysis based on the SGR, in which better growth performance, antioxidative ability and flesh quality were observed in T. ovatus juveniles.  相似文献   

15.
Red porgies, Pagrus pagrus L., were fasted for 7, 14 or 28 days, and were then allowed to feed on pellets released from demand feeders. Biological responses during fasting and refeeding were examined. The factors considered were growth, organosomatic indices and proximate body composition (protein, fat, ash and moisture). Fasted red porgies lost weight and had higher relative weights of eviscerated body than control fish. Refeeding was accompanied by hyperphagy, which resulted in similar total food demand being shown by all groups. Fish which had been deprived of food displayed compensatory growth and the final weights of these fish at the end of the experiment were similar to controls. There were no significant changes caused by fasting in the relative proportion of body chemical components. Calculations based upon changes in protein and lipid content suggest that more protein than lipid is metabolized during the first phase (14 days) of a fast.  相似文献   

16.
为研究水体盐度和饲料脂肪含量对尼罗罗非鱼生长、营养组成和肉质的影响,本实验设置0、8和16共3个盐度梯度,每个梯度分别投喂中脂(6%)和高脂(12%)饲料,投喂初始体质量为(5.0±0.2) g的尼罗罗非鱼8周,并测定生长性能、血清生化指标、肌肉营养成分和肉质相关指标。结果显示,在中脂饲料投喂下,与对照组(盐度为0)和高盐组(盐度为16)相比,中盐组(盐度为8)的尼罗罗非鱼具有最大终末体质量、躯壳比、脂体比、肌肉蛋白质含量、肌肉氨基酸和乳酸含量和总产肉率,但其饲料系数、脏体比、肝体比和肌肉p H值显著降低;而中脂高盐组的尼罗罗非鱼其饲料系数、肥满度、脏体比、肝体比、全鱼总脂、肝脏甘油三酯、血糖、血清乳酸和血清甘油三酯含量、血清谷草转氨酶活性较高,但全鱼和肌肉水分、全鱼灰分、产肉率和肌肉离心失水率降低。在高脂饲料投喂下,随着盐度的上升,其终末体质量、成活率和脂体比降低,但饲料系数、脏体比、肝体比和肥满度增大。其中,高脂中盐组尼罗罗非鱼的肌肉蛋白以及氨基酸含量显著降低,而高脂高盐组的全鱼灰分、肝脏甘油三酯、血糖、谷草转氨酶活性、肌肉总脂、肌肉甘油三酯和磷脂含量显著提高,但全鱼总脂、肝糖原、产肉率、肌肉离心失水率和pH值显著降低。而不论在淡水还是盐水养殖情况下,与中脂饲料组相比,高脂饲料组尼罗罗非鱼均显示出更高的脂肪积累量和肌肉乳酸含量,以及更低的成活率和产肉率。尤其在高盐度水体中,高脂饲料对尼罗罗非鱼肌肉脂肪和乳酸积累的促进作用和对成活率、饲料系数和产肉率的负面作用尤为明显。研究表明,在中脂饲料投喂下,适宜的盐度(盐度8)可以促进尼罗罗非鱼的生长并提高肌肉品质,然而,在高盐度水体中使用高脂饲料对尼罗罗非鱼的生长与肉质则有较大的负面影响。  相似文献   

17.
The relationship between body size and the depletion of white muscle metabolites (e.g., PCr, ATP, glucose and glycogen) was examined in two sizes (30 or 700 g) of rainbow trout deprived of food for one, four or seven days at either 5 or 15 °C. Following 7 days of food deprivation at 15 °C, the levels of muscle glycogen decreased by approximately 50% in small fish relative to control values (i.e., day 1). In comparison, small fish acclimated to cold temperatures did not exhibit a significant reduction of muscle glycogen over the seven day fasting regime. In contrast to small fish, the levels of white muscle glycogen in large fish remained unchanged after food deprivation, regardless of acclimation temperature. A seven day deprivation of food also resulted in a 50% depletion of white muscle glucose concentrations in small and large fish acclimated to warm temperatures, but there were no significant changes in this variable in fish acclimated to cold temperatures. In contrast to the negative effects of food deprivation on white muscle glycogen and glucose levels, the concentrations of white muscle PCr and ATP were not greatly affected by food deprivation under any of the experimental conditions. Taken together, these results clearly show that food deprivation can have an important influence on the storage of energy metabolites for anaerobic energy production, particularly in small fish at warm temperatures. In the future, it may be very important to consider the physiological effects of short-term food deprivation when interpreting results from studies in which fish have been fasted prior to treatments such as exercise.  相似文献   

18.
Production of triploid turbot is a relevant goal for the aquaculture industry due to the benefits associated with their sterility and growth. In order for a better understanding of the final quality of the species, muscle cellularity and quality parameters of the flesh were studied in seven diploid and seven triploid turbot after sexual maturation. White muscle cellularity was evaluated throughout white muscle cross‐sectional area from the epaxial left muscle section of each fish. To ascertain the flesh quality, several physico‐chemical parameters (moisture, ash, protein, total fat, fatty acids and minerals) were analysed, and textural mechanical properties (springiness, hardness, chewiness, cohesiveness, gumminess and adhesiveness) were determined objectively with a texturometer. Muscle cellularity was different between both groups, such that muscle fibre density was higher for diploid specimens (P < 0.001) and muscle fibres diameters were higher for triploids (P < 0.001). Both ploidy groups showed no significant differences in moisture, ash, protein and total fat content (P > 0.05). All textural properties analysed showed no significant differences between both ploidy groups (P > 0.05). In both ploidy groups, fibre density and fibre diameter showed no significant correlations (P > 0.05) with textural parameters such as springiness, cohesiveness, chewiness and adhesiveness. Ploidy did not affect fatty acid composition, with the exception of eicosapentaenoic acid (C20:5ω3) which was higher in the triploid group. No significant differences (P > 0.05) existed between diploid and triploid turbot in content of all minerals analysed. According to our results, the ploidy status determines significant variations on muscle cellularity but does not influence the flesh quality of the turbot.  相似文献   

19.
A 120-day feeding trial was conducted to determine growth, feeding efficiency, and biochemical composition of juvenile spotted babylon Babylonia areolata (initial mean weight of 1.48 ± 0.06 g) fed on conventional trash fish and a formulated moist diet in a flow-through grow-out system. The snails readily accepted the formulated moist diet and showed good growth and survival during the trial. There were no significant differences in specific growth rate, feeding efficiency, and survival between the snails fed on trash fish or the formulated moist diet. At the end of the experiment, biochemical analysis of the snail flesh showed significant differences in flesh quality, with the snails fed on trash fish having a significantly higher crude protein compared to those fed on the formulated diet, but there was little difference in crude lipid content. Whole body tissue of snails fed on trash fish had significantly higher total amino acid, essential amino acid, and non-essential amino acid levels compared to those fed the formulated diet. This study showed that the formulated moist diet can be readily used for B. areolata growout for maximizing growth, survival, and feeding efficiency; however, further research is needed to improve the flesh quality particularly amino acid and fatty acid levels before its suitability for B. areolata is assured.  相似文献   

20.
To investigate the effect of dietary folic acid on fish flesh quality, muscle antioxidant status and the potential mechanism, young grass carp (Ctenopharyngodon idella) were fed diets containing 0.10–3.12 mg/kg diet of folic acid for 8 weeks. The results showed that optimum folic acid increased muscle contents of protein, lipid, pH, shear force, amino acids, unsaturated fatty acids, hydroxyproline and glutathione, whereas contents of moisture, cooking loss, lactate and saturated fatty acids and cathepsin L activity showed an opposite trend (p < .05). Moreover, optimum folic acid elevated antioxidant enzyme activities and mRNA levels, as well as NF‐E2‐related factor 2 and casein kinase 2 mRNA levels (p < .05). However, optimum folic acid decreased reactive oxygen species (ROS) content and Kelch‐like ECH‐associated protein 1a (Keap1a) and Keap1b mRNA levels (p < .05). Interestingly, excess folic acid induced negative effects on above‐mentioned parameters (p < .05). Summarily, this study indicated that optimum folic acid improved fish flesh quality and muscle antioxidant system associated with Nrf2‐Keap1 pathway. Based on muscle cathepsin L activity and ROS content, the folic acid requirements for young grass carp were 1.87 and 1.80 mg/kg diet, respectively, regarding to the flesh quality and antioxidant status.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号